When artificial materials are implanted into bone defects,
they are encapsulated by fibrous tissues and isolated from surrounding bone.
This is a normal protective response of living body.
However, some artificial materials with specific composition and structure can bond to living bone tightly.
They are already commercialized as bioactive artificial bone.
However, novel artificial bones with higher bon-bonding ability are required in orthopedic field.
In order to obtain such excellent bioactive artificial bones,
it is essential to control physical properties as well as chemical and biological properties of materials.
Figure 1 shows concept of titanium metal with ex vivo antibacterial property and in vivo bioactivity.

In addition, recently, it is found that radioactive or magnetic microspheres
with 25 micron diameter can be infused the neighborhood of tumor,
and treat cancer cells locally by irradiation of beta-ray or heat.
Figure 2 shows concept of intra-arterial therapy of deep-seated cancer
by using radioactive or magnetic microspheres (a)
and suppression of tumor growth by infusion of radioactive yttrium oxide microspheres (b).
We must further optimize the structure of the microspheres to enhance the therapeutic efficacy.

In our laboratory, we try to develop "novel biomedical materials for bone-repair or cancer treatment".